guest ::
| Home > Publications database > Zusammensetzung der Kohlenwasserstoffe im Abgas unterschiedlicher Fahrzeugkonzepte |
| Home > Publications database > Zusammensetzung der Kohlenwasserstoffe im Abgas unterschiedlicher Fahrzeugkonzepte |
| Book | PreJuSER-39889 |
; ;
1999
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag
Jülich
Please use a persistent id in citations: http://hdl.handle.net/2128/13155
Report No.: Juel-3646
Abstract: In this study the exhaust gas of cars equipped with different engine types, i .e. cars with diesel engines, cars with petrol engines and three-way-catalysts, and cars with petrol engines without catalysts was anaiysed . Five cars of each engine type were measured on a chassis dynarnometer under conditions of the US-75 test procedure and the „Autobahn" Lest. The emission factors of CO, NO,, total HC, particles and CO2 were determined . In addition, measurements of 45 different hydrocarbons, 9 different carbonyles, phenole and the surrt of the cresoles were performed. The influence of the cold start phase and the mean velocity on the composition of the car exhaust was analysed with special emphasis on the individual VOC's (VOC-split). For this purpose, the different phases of the test cycies were regarded separateiy. The cars equipped with a three way catalyst showed the largest span of the emission factors in grams per kilometre over the different test phases . The highest emissions of hydrocarbons and carbonyles were observed during the cold starr (first phase of the US-75 test) rohen the catalyst is not or not fully active . Compared to the cold start the emissions are reduced by a factor of 10 to 20 in the other phases of the US-75 test . On the other hand with higher mean velocities as driven in the „Autobahn" test an increase of the emissions nearly up to the level of the cold start emissions was observed . This effect is due to the change of the air-fuel-ratio . When high loads are needed, more fuel is added and therefore the conversion efficiency of the catalyst is decreasing. The VOC split was analysed by grouping the individual VOC into five different substance ciasses : alkanes, aikenes, aromatics, carbonyles and phenoles . For cars with three-way-catalysts sarge changes in the VOC split were observed for the different Lest phases, In the cold-start phase the contribution of aromatic compounds was largest, followed by alkanes and alkanes. In the warm phases of the US-75 alkanes are the most prominent substance class . In the autobahn test the contribution of the aromatics increases with increasing mean velocity. For cars with diesel engines and cars without a catalyst the effect of cold Start conditions on the emissions is not as obvious as for the cars with catalysts . For both car types the emissions of carbonyles and hydrocarbons in grams per kilometre are higher in the US-75 fest than in the „Autobahn" Lest . The variation of the VOC split for the different test phases is also much lass pronounced than for vehicles with catalysts . For higher mean velocities only small changes in the VOC split were observed. The effects of the different amounts of VOC-emissions and the different VOC-splits on tropospheric ozone formation were assessed by calculating the ozone forming potential (OFP). The highest OFP values were calculated for the cars without catalyst, because of their highest VOC mass emissions and the high reactive VOC-split . Cars with catalyst show very Iow OFP values at Iow mean velocities . With increasing mean velocities the OFFvalues are also increasing . In contrast, for cars with diesel a decrease of OFP-values is found with increasing mean velocity .
|
The record appears in these collections: |
PDF
Fulltext by OpenAccess repository